Fast brown leather dyesttjffs and a



Patented Feb. 8, 1938 UNITED STATES PATENT OFFICE FAST BROWN LEATHER DYESTUFFS AND A PROCESS OF PREPARING THEM Fritz Hess, Karl Hager, and Walter Pense, Frankfort-on-the-Main-Hochst, Germany, assignors to General Aniline Works, Inc., New York, N. Y., a corporation of Delaware No Drawing. Application November 26, 1935, Serial No. 51,680. In Germany November 30,

4 Claims.

the one phenyl nucleus a nitro group and in the The dyestuff has the following constitution:

s oqona SOgONa olN HN 0H3 NH SOaONa \O/\ SOQQNB other phenyl nucleus an amino group, there are (2) The aqueous solution of the dimtro-aminoobtained fast brown leather dyestufis which have diphenylamine-disulfonic acid, obtainable by conthe valuable property of penetrating deeply into densing in a solution alkaline with sodium carthe leather during the dyeing process and of dyebonate 19 parts of lA-diaminobenzenesulfonic ing in many cases even the whole core of the acid with 29 parts of 1chloro-2.6-dinitrobenleather. This favorable effect could not be exzenesulfonic acid, is stirred for 8 to 10 hours at pected in view of the large size of the dyestuif 50 C. with 13 parts of toluquinone and 15 parts molecule. The dyestuffs are new. There are obof a pyrolusite powder of 85 per cent. strength. tained, for instance, dyestuffs of the following The deep brown solution thus obtained is filtered general formula: and sodium chloride is added. The dyestufi sOlONa o soiona XJVNER SOONa solona -1- u u N0: V Y N02 wherein X means hydrogen, methyl or chlorine. The following examples serve to illustrate the invention, but they are not intended to limit it thereto, the parts being by weight:

(1) The aqueous solution of the nitroaminodiphenylaminedisulfonic acid, obtainable by condensing 37.6 parts of 1.4-diaminobenzenesulfonic acid and 47.5 parts of l-nitrochlorobenzenesulfonic acid in a solution alkaline with sodium carbonate, is stirred, for 8 hours at 50 C., with 25 parts of toluquinone and 20 parts of pyrolusite of per cent. strength in the form of powder. The solution which is at first yellowish-red becomes a deep brown; it is filtered after the time indicated. The filtrate is rendered acid to Congo paper by means of hydrochloric acid, whereby the dyestuff acid is precipitated. It is filtered with suction, rendered alkaline by means of sodium carbonate or ammonia and evaporated. About '75 parts of leather dyestufi are obtained.

which is thus salted out is filtered with suction and dried. 45 parts of leather dyestuff are obtained. The dyestuff has the following constitution:

SOzONa N02 N02 (H) O/HN wrung I /SO2ONE mools Una on, NH/ N02 N01 S OaONa If 1-chloro-2,4-dinitrobenzenesulfonic acid is substituted for the 1-chloro-2,6-dinitrobenzenesulfonic acid, the process takes an analogous course.

(3) The condensation product from 27 parts of 1,4-diaminobenzenedisulfonic acid and 24 parts of 4-nitrochlorobenzenesu1fonic acid is stirred in an aqueous solution with addition of 6 parts of calcined sodium carbonate for several hours at 50 C. to 60 C. with 12.5 parts of chloranil. The solution which is at first yellow becomes a dark brown. It is filtered and the filtrate is evaporated.

which is evaporated to dryness. 55 to 60 parts of the product are obtained which dyes leather brown tints. The dyestufi' has the following 1. The compounds of the general formula:

some 0 some SI OzONa IRA/NH sozona 1| n 1 l NO: HN/Y\X N01 (4) To an aqueous solution of the condensation product from 19 parts of 1,3-diaminobenzene-sulfonic acid and 26 parts of the sodium salt of 4-nitrochlorobenzenesulfonic acid, there wherein X means a member of the group consisting of hydrogen, methyl and chlorine, dyeing leather brown tints of good fastness properties.

2. The compound of the formula:

soloNa SOiONB /O HN NNHU No: olN UHN UCHa \NHQ are added, while stirring, 16.5 parts of toluquinone in the form of a paste and 10 parts of pyrolusite of per cent. strength and the mass is kept for 10 hours at 50 C. to 55 C.; it is then SOaONB. O SOzONa which represents a fast brown leather dyestuff having the valuable property of penetrating deeply into the leather during the dyeing process.

3. The compound of the formula:

lI IOz (f SOzONa NO: O/HN\O II) II NHU JO somm Naools l I HN om NH I N01 some 0 N02 filtered hot, the filtrate is rendered acid to Congo paper by means of hydrochloric acid and the dyestufi which is precipitated is filtered by suction. The solid matter is rendered feebly aklabeing a fast brown leather dyestuff which has the valuable property of penetrating deeply into the leather during the dyeing process.

4. The compound of the formula:

SOzONs O SOaONa N0 ORA/NR NH QZZQHNYQLO Us line and evaporated. 50 parts of a dyestufi are obtained which dyes leather deep brown tints.

(5) By using in the preceding example instead of toluquinone and pyrolusite, 12 parts of chloranil and 6 parts of sodium carbonate and boiling for 20 hours, a deep brown solution is obtained,

OzONB being a fast brown leather dyestuff which has the valuable property of penetrating deeply into the leather during the dyeing process.

FRITZ HESS. KARL HAGER'. WALTER PENSE. 

